This invention relates to the detection and identification of a diseased or impaired organ in a human patient. The desirability of a laboratory test as an aid to pinpointing the nature of an ailment has been long recognized because of the facts that (1) different disease conditions may manifest similar symptoms, and (2) the same disease condition may produce different symptoms in different patients.
It has been observed by prior workers in the field that certain disease conditions in certain organs of the body, such as the heart, liver, kidney, skeletal muscle, or lung, produce abnormal substances in the blood of the patient and diagnostic systems have been proposed which are based on the detection of these abnormal substances where they are present. Diagnostic systems are also in use in which materials normally present in the blood of a healthy human being are detected and measured in the blood of a patient to ascertain whether any of these materials is present in the patient's blood in an abnormal amount.
The present invention is based upon a different principle and upon the discovery that in certain abnormal conditions in a human organ there is a "spilling over" into the bloodstream of substances which are present in that organ when it is in a normal, healthy condition but which are not ordinarily present in substantial concentrations in the blood of a healthy human being.